Searchlight



sept. 21, 1926. 1,000,840

-i E. J. MURPHY ET AL SEABCHLIGHT Filed July 9, 1920 5 Sheets-Sheet l'Inventors Edwin lmurpng, Le nard P. Hutt,

Their` Attorneg.

` sept. 21 192s. 1,600,840

E, J. MURPHY ET AL SEARCJHLIGHT Filed July 9. 1920 3 Sheets-Sheet 2Inventors;

Edwin J. murphg, Leonard P. Hutt,

f3 l ThehA Attorney.

Sept. 21 1926.A 1,600,840

E. J. MURPHY ET Al.

SEARCHLIGHT Filed July 9, 1920 5 Sheets-Sheet 5 Inventors. EdwmJ. murphyLeo ard P. Hutt,

b5 4 T heir` Attorneg Patented Sept. 2l, 1926.

UNITED STATES PATENT OFFICE.

EDWIN J'. MURPHY AND LEONARD I. HUTT, OF SCHENECTADY, NEW YORK`ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SEARCHLIGHT.

Application filed July 9,

Our invention has reference to improvements in searchlights, and morespecifically to a new design of arc lamp and ventnation system for usein connection therewith. The arc lamp is usually housed in a barrelequipped with a suitable reflector at one end. Its opposite end may ormay not have a window, our invention being adapted both to the open orclosed type of searclilights.

One object of our invention is to provide a rugged, compact andeilicient lamp unit, which may be readily placed iin and removed fromthe searchlight barrel, and electrically connected and disconnected withthe operating circuit. This unit consistsof a posit-ive and a negativeelectrode holder or head, the positive hea-d being arranged with theelectrode in a horizontal plane, while the negative head has itselectrode inclined at an angle pointing upwardly toward the crater endof the posit-ive elect-rode, in accordance with the usual arrangement inmodein high intensity are lamps of this general character. A mechanismis provided adjacent the positive head for rotating the anode about itsaxis and for feet ing it forwardly to compensate for consumption. Thenegative head is also provided with a. forward feeding mechanism. Theelectrode heads and the feeding mechanism for the negative electrodeform a conipact unit, which is provided with convenient handles forplacing it in position. These handles also are arranged to make theelectrical connections between the lamp t and the main circuit.

Another object of our invention is to provide a novel system ofventilation to expel hot gases and smoke from the barrel and to cool theelectrode heads, the barrel and the reflector. Heretofore it has beennecessary to resort to forced draft ventilation in which motor drivenfan is used, since the natural ordinary draft was insu'lilicient,especially in high intensity searchlights. has also been found that onsome occasions it is necessary to operate the seaichlight at all anglesof observation, for instance when exploring the sky for aircraft, whichmade the use of the forced draft difficult. Our system depends entirelyupon the natural draft or chimney effect of the heated g: le surroundthe arc with a metal chamber, open towards the mirror, and extending1920.v Serial No. 394,872.

from the bottom and top are two similar draft tubes or chimneys, soarranged that either one or both of these tubes are disposed above thechamber at all angles of elevation of the searchlight. Therefore, in allpositions, the gravity effect of the heated gases will produce theproper chimney action to expel the hot gases and smoke.

Other objects and purposes"\of our invention will appear in the courseof the following .specification in which we have shown our inventionembodied in concrete form for purposes of illustration.

In the accompanying drawings, Fig a side elevation of the lamp unit; I

Fig. 2 is a side view, partly in section of thevnegative and positiveelectrode heads; li ig. 3 is a detail view of a part of Fig. l f

f l n Fig. l is a perspective view of part of the .lis

-mechanism for feeding the positive electrode;

`F ig. 5 is a section taken on the line .55 of Fig. l, looking in thedirection of the arrow indicated and showing the mechanism for feedingthe positive electrode;

h Fig. 6 is a perspective view of a searchlight embodying our invention;

Fig. 7 is a perspective view of a searchliglit drum embodying ourventilation system, with our lamp unit shown in a transitory orsuspended position;

Fig. 8 is a side view, partly in section of a closed drum type ofsearchlight, equipped with oui Ventilating system;

- Fig. 9 is a front view of the closed barrel type of searchlight shownin Fig. 8, with part of the ventilator omitted; and

Fig. l() is a perspective view of part of one of the ventilatingchimneys.

Referring to the drawings, there is shown in Fig. l a lamp unit whichconsists of a positive electrode head A and a negative electrode head B,which are each fully described liereinafter. These heads are secured toa common supporting plate l, to form the lamp unit shown.

A positive electrode 2, is supported in a central bore of a casting orframe 3, which frame is provided with a number of eX- ternal radiatingribs 4. The plate l has a suitable opening though which a part of theframe 3 projects until the rib 5 nearest this end engages the plate. Theframe 3 is insulated from the plate l by a washer 6,

of mica or other suitable insulating material, and is suitably securedto said plate, as by a screw 7, which screw is surrounded by aninsulating` Sleeve S. The end ot' the frame 3 passing through the plate1 has a wide flanged member T of suitable material, preferably o1Ecalorized copper set into and secured to it; the of this meml deflectthe arc Frame `'rom the main body t-he positive holder and is called anobdurator. At its opposite end, the ifaine 3 has a slot on its underside, extending to the f tral bore in the frame, into which is sl 1..--bly litted a silver faced blot-,lt or contact` 5) normally urged intothe central bore by a spring 10. This inward movement limited b v aliange 11 on the Contact il engaging the frame Yv'hen an eleetrode 2pushed into the central bore o? the :trame 3, the eentaet 9 will beurget into elo-Se engagement with the electrode, thereby ma ring a goedelectrical connection.

The casting),` is formed with a a rm 12 at one end, as shown in Fig'. 2,provided with a. handle 18, ot any suitable insulating material, such aswood or rubber.

The positive electrode 2, is arranged to move toward and away from thenegative head B and to rotate about its own axis. This is accomplishedby a mechanism con- Sistina ot a trame or stationary cage, indicated asa whole by the numeral 15, and a smaller cage indicated by the numeral10. journaled within the eagle 15.

The frame 15 is formed at one end by a circular member 17 having' ailanged enter edge, which member is rigidly secured in any suitablemanner to the base plate 1, such as by a number of legs 18, whichstraddle the frame The other end of the frame 15 is formed by a circularmember 19, somewhat similar to the member 1T, ano is united to saidmember 1T by a number of parallel rods 20, as shown in Fig. 1.

The member 1.7 is provided with a eentrf opening' 21, formed with asmall tubular extension shown in Fig. 2, which Serves as a bearing' forthe inner cage 1G and a paesage tor the. positive electrode. The member19 likewise has a central tubular extension 22, shown in Fig. 3, whichserves as a bearing for the rear end of the inner cage 1G. i

The inner cage 16 is formed atone end with a bevel gear 23 which has acentral tubular extension 21, arranged to lit into the opening` 21, as.shown in Fin'. 2. The rear end of the cage 16 is Jormed of a eirenlarmember 25, which also has a central tubular extension 2G, as shown inFig. 3. This tubular extension 2G lits over tlie tubular extension ofthe opening` 22, which latter e;- tension has been somewhat reduced inSize to form a shoulder against which thev nie ber 26 abuts. The gear 23and member are eonneeted to each other by three parallel rods 2T. TheCage 16 is also provided with a long,l screw 2S, journaled at its endseccentrically in the gear 23 and member 25, respectively. A carriage 2f)is arranged to slide on the rods 2T in a suitable manner, and it hasformed in it a nut which engages the Screw 28. This carriage is providedwith a screw clamp, indicated by the numeral 250 in L* et, forclamping,r the rear end of the electrode 2.

From the foregoing it appears that the positive electrode 2 pai-zegesthrough the eentral bore o1 the frame 3, the member 24:, and is atitsrear end securely clamped to the inner cage by the clamp 10. This clampis properly insulated from the carriage 2), as by mica sleeves 31.Therefore, the electrode 2 may be rotated about its own axis by rotatingthe cage 16. which done by rotatinO' a bevel pinion 32. mounted on themember 1T and whieh meshes with the bevel 23 of the cage 1G.

The forward and baekward niovement ot' the electrode 2 obtained byrotating the sere f' which causes the carriage 2? to move. Tt isdesirable to teed the electrode, or move it torwart1 and rotate itsinmltaneously. The rotational movement aeconr plished through therotation of the bevel pin' in small star whee $13 secureil on the Screw28 near the forward end of the cage 16, and is arranged to strike adetent 8l n'iounted on the Stationary eagle 15, once dm'inea chrevolution of the inner ca ee 143, as show. in Figi. 5. This gives apartial rotation to Screw LS, and thereby a short movement to theelectrode. It is obvious that the distance through whieh the eleetredeie n'ioved by each revolution ot' the cage 16 is determined by the pitchot' the Screw 2S and by the Spacing of the points ot the star wheel.Sometimes it is desirable to move the electrode baixward and Jforwardrapidly without rotating; it, Jfor example. when a new electrode isplaced in the lamp. For this purpose we have mounted on the screw 2S asmall wheel which may be readily rotated by the hngers.

The negative electrode 10 is supported in a ventral bore ot a frame orcasting #l1 which is rigidly seeureo at one end to a Supporting' arm4-2, and in Conductive relation therewith, as shown in Fin'. 2.

The suppertiner arm is secured to the bae plate 1 by serews 1121. one of.vhieb ia exposed in Fie'. Cv)z the arm suitably inauated trom late. asby a mica washer The arm so curved that the neri tive eleetrode will beheld at a predeterthe positive electrode an angle of 1110 raving beenfound suitable. +3153 also Secure to the ba e plate 1 an arm 5, whieh isinsulated from the plate 1 by a` mica washer etti. Insulating minedangle to l lit) sleeves 46 surround the screws 43, which serve asconductors between the arm and the arm 42, and insulate them from theplate 1. The arm 45 is provided with a handle 47, of insulatingmaterial, such as wood or rubber. It will also be seen that the arm 45has a lug l0 against which the spring 10 bears, and from which it issuitably insulated such as by mica washers 11.

At its free end, the casting 41 forms a nozzle 48 which gradually taperstowards its end. Near its opposite end, the casting 41 is formedU-shaped, as indicated at 49, which serves as a housing or supporting`means for the negative electrode feeding mechanism.

The portion of the casting uniting the structure 49 with the nozzle 48is of cyliA drical formation and is provided with vertical openings orslotsto accoi'nmodatc electric contacts bearing upon the electrode. Asilver contact block 50 is rigidly secured in the lower slot; it extendsinwardly a slight distance beyond the wall of the central bore, so thatit will hold the electrode clear of the casting. A silver brush 51loosely fits in the upper slot so that it may engage the electrode andmake a good contact with the same. The contact block 50 is connected byan elastic silver band 52 with the brush 51 and is bent around theIcylindrical portion of the casting 41, between the U-shaped structure 49and the nozzle 48, which band is suitably secured to said block andbrush by screws 53. The band 52, in addition to serving as a conductingbridge between the contact 50 and brush 51, also resiliently holds thebrush 51 in the upper slot.

The negative electrode feeding mechanism comprises a vertical support 54suitably mounted in the U-shaped structure 49 and insulated from it.This support may be secured in position in any suitable manner, such asby providing it with a threadef end, which projects through an openingin the bottom of the U-shaped structure and securing it with a washerand nut 55. An axle 56 is journaled in a plane below the edge of thecentral bore in the support 54; it carries two gears 57 and 58, theformer of which is somewhat smaller than the latter, and of suchdiameter that when an electrode rests on the contact block 50, theelectrode will be in frictional engagement at its lowermost surface withsaid gear 57.

A lever 6() is pivoted at 61 on the leg 62 of the U-shaped structure 49.A second lever 63 is pivoted to the end of lever 60 at 64, as shown inFig. 2. At one end the lever 63, has a vertical support 65, extendingdownwardly in the same plane with support 54, and similar in shape withthe latter. The support 65 may be secured to the lever 63 in anysuitable manner by prefer ence in the manner in which support 54 issecured to structure 49.. An aXle 66 is journaled in a plane above theedge of the central bore in the support 65 and carries two gears 67 and68, preferably oi the same size as gears 57 and 58 respectively.

At its opposite end, the lever 68 is formed with an arm 7 0 which restson the silver band 52 directly over the brush 51. An eX- pansion spring71 is interposed between the end 72, of the lever 60 and the end 78 ofthe casting 41. The lever 6() is curved to one side so that the spring71 will not inten fiere with the movement of the electrode through thecentral bore.

Obviously, the force of the expansion spring 71 will cause the lever 60ulcrumed at 61 to press downwardly at 64. This pressure at 64 istransmitted to the lever 63, which exerts a downward pressure on the armand the aXleGG. The pressure exert ed upon the arm 70 is transmitted tothe movable silver Contact 51, so that the electrode is properly heldbetween the contact 50 and brush 51.

The force exerted upon the axle 66 causes the gear 67 to frictionallyengage the electrode on its uppermost surface, and brings the gear 68 inmesh with gear 58. A suitable rotating mechanism is secured to the axle56, such as a slidably connected rod 74 with a. turn button 75, as shownin Fig. 6.

The negative electrode is pushed through the central opening of thecasting 41 which raises the gear 67 and releases the brush 5l., therebypermitting the free passage of the electrode through the nozzle 48. Thespring 71 causes the electrode to be engaged between the contact 5() andbrush 51 and bctween the gears 57 and 67 in a manner readily understood.Obviously, by rotating the axle 56 in a clockwise direction, the gears58 and 68 will cause the electrode to move toward and through the noselt is, of course, understood that while the electrode is snugly engaged.by the contacts 50 and 51, such engagement is not sufficiently rigid toprevent a sliding movement between them when the axle 56 is rotated.

The electric circuit through the lamp unit thus far described is fromthe positive side of the source to arm 12 and the Y,Frame 8, through abraided conductor 9 to the silver Contact block 9 and the electrode 2,across the arc to the negative electrode 40, contacts 50 and 51, throughthe frame 41, the arm 42, screws 48, and arm 45, to the negative side oithe line. The connection of the line with arm 12 and arm 45 will bepointed further on.

In Figs. 6 and 7 is shown an open type of searchlight of drumconstruction.l formed of a circular frame. or ring 100, to which issecured on one side a barrel 101. forming the wall of the searchlight,and to the opposite side a retlector 102, by Kcreivs 103, or in anyother suitable manner, thereby closing one end ot the barrel 101.

A ventilator, designated a Whole by the numeral 104, is preferablyformed of one casting ot a length corresponding; to the inside diameteror" the baiel 101, and it also serves as the supportingl :trame tor thelamp unit described, as will presently appear. ator casting;` 101 has anopen central chamber its ends, the opening o' parallel vfith the anis ofthe Jformed With t or chimney elements 10G and 10T trom the chamber 105,as shown i' which are bent outwardly at their ends. This casting` issupp trio arms 10S and 10?, which may part ot the casting` and which aisecured to the trame ring- 100. These aupportinn arms are ot the properlength to so locate the chamber 105 that the focus ot the reflectorcomes Within the chamaer.

The chimneys and 10T are by similar tubular memberi 110 respectively,which extend nearly angles to chimney members 100, are rigidly securedto the casting` 'form continuous chimneys from eic oi? the chamber 105.The memberi: i 111 pass out of the open end of "he and bent near theirends ii a di re outivai'tV lr and vav from the chamber Y i he ventilsaid chamber heil D barrel 101. vi'o tubes le, n

The ends of these members are Cappelh with eoivls and 113.

rlhe barrel 101 is mounted on a yoke 111 in the usual manner to permittl e movement ot the searchlig'ht through all andes of eleration by thehand Wheels 11i. As shown in the uravfing, the casting' 104v is mountedin plan at right angles to the movement of the barrel in the yolie, sothat either or both ot the draft tubes 110 and 111 a e disposed abovethe chamber all angles ot elevation of the searchligiht.

The draft tubes and 111 are provided with dampers S0, one ot which isindicated in Fig'. 10. rllhese dampers are pivote-d at 11G ai d 11Trespectively, Which points it will be observed are on the inner side otthe tubes, or the near side to the chamber 105, so that the damper Willdrop to open position in the uppermost tube and to a e.; position in theother, in practically all positions ol' the searchlieht. and when not inthese positions, both dampers Will be open, for instance, vfhen theeleY-.fation ot tue searehlight is 90 degrees. rl`he operation ot thesedampers is automatic, and their movement controlled by gravity.

The conductor 11S from the po .side ot the line is preterably led upthroren the tripod 119 or other suppcrt of' tno, tearehhght, around thebarrel 101. rhis threaded hole 128, similar to the hole i. From thedrawings, it will be seen tha the casting 101- is provided with a pin1210 on 1h side ot the chamber 105.

the drum by and 41T. and

1 has tifo openings 131inear its upper ovrer ends respectively, arrangedto be .n yed by the pins 130 on the` casting; 101. The lamp unit ispushed toi-Ward in the chamber 105 until the plate 1 ene ges the 1.0-11and the pins 130 emV ye the holes 1o 1, which leaves the lamp unitsupported by the casting 101 on said pins. It ivill also be seen thatthe chamber 105 is tl. roby closed by the plate 1, on itsl outer end,that is, the end aivay from the retlect r, and its inner end remainsopen. As stated hereinbetore, the chamber 105 occupies a. positionSurrounding the focal point and the various parts of the lamp unit andthe supportingcasting' 10-1 are so coordinated that the are. may be inthe focus. As described above, the electric circuit throreh the lampunit is from arm 12 to the arm rThe arm 12 is noiv connected to thepositive side ot the line by means of a screw of the handle 13, engagingthev hole of terminal 1241, and the negative side is similarly connectedby a screv.- 33 of handle engaging hole 128 oit terminal 12T. thisarrangement the lamp may be readily placed iu or removed from the drumand the electrical connections established at the same time.

ln order to be able to operate the elec trede feeding and rotatingmechanism from the outside ot the searchlight drum, and at the same timenot interfere vrith the easy remo val or replacement ot the lamp unit inthe drum, We have slidably connected operating' handles to themechanism. In Fie. 5 is shown the operating handle 150 tor the positiveelectrode which is fed byY rotating the bevel pinion 32 as described.

rllhis handle which is mounted on the hand Wheel 11dl is pivotallyconnected to a rod 151, which passes through the member 152 on the shaftof pinion A pin 153 on the shaft 151 lits into a slot in member and asis readily undestood, imparts the motion of the shaft to the pinion. Theshaft 151 passes through a cylindrical chamber 154, formed on the handwheel 114l in which `an expansion spring 155 bearing against a collar156 on the shaft 151 normally urges the shaft inwardly towards the lampunit. The handle 151 is formed with a convex cam surface bearing at onepoint against the surface of the hand Wheel. Therefore, by rocking thehandle, the spring 154 will be compressed and the shaft 151 drawn fromthe slot 152, leaving the lamp unit free to be removed. With referenceto the negative electrode, the shaft 56 is rotated by a handle 7 5,connected to a rod 74 in a manner identical with that described withrespect to the handle 150 and rod 151 of' the positive electrode. InFig. 6 the handle 75 is shown in the form of a button, but otherwise themechanism is the saine as described for the positive electrode. The handwheel 114 also has the usual screen 157 for viewing the arc. Asemi-circular shield 158 is mounted on or forms a part of the casting104 to permit an unobstructed View of the arc.

When our invention is used with a closed drum type of searchlight, awindow 160 is fitted tothe barrel 101 in any suitable manner, and isprovided with two suitable open ings 161 through which the chimney ordraft members 110 and 111 may pass and a suitable central opening 162for the lamp unit, as shown, in Fig. 9. From Fig. S it will be seen thatthe casting 104 iis positioned in the barrel slightly below the outeredge ot the barrel and that the elbow ends of. the chimney parts 106 and107 thereof project slightly beyond the edge of the barrel. Therefore,when the window is in lace, the ends of chimneys 106 and 107 pro jectthrough the openings 161. Chimney extensions 110 and 111 are secured toparts 106 and 107 respectively, for this purpose the parts 106 and 107are each provided with a flanged edge, having inwardly directed hooks170. These Vlianges are each also provided with a set of openings 171oli which one opening is shown in Fig. 8.

The parts 110 and 111 each also have a flanged edge arranged to fit theflange of chimneys 106 and 107 respectively. llhese flanges also have aset of pins 172 arranged to fit the openings 171 and thus prevent theparts 110 and 111 from slipping out of position. The parts 110 and 111are securely held against the chimney parts by means of a set of curvedlevers 173 pivoted to each of said parts and provided with rings 174arranged to fit over the hooks 170 as shown in Fig. 8, and thereby lockthe parts in position in a manner readily understood. The lamp unit maybe readily fitted to the casting 104 through the opening 162 in the samemanner as if the glass window were not used.

What we claim as new anddesre to selight, a drinn, a reflector and aventilating' system ail mounted to rotate about a hori- Zontal axis,said system having a chamber surrounding the source of light and open atits end toward the reflector, tubes extend ing from the chamber out ofthe drum in opposite directions from each other and at a substantialangle to the axis about which the searchlight rotates whereby one of thetubes acts as a chimney at all angles of elevation of the searchlight.

3. A searchlight comprising an are lamp having a light emitting element,a drum mounted to rotate about a horizontal axis, a reflector and aVentilating system, the latter having an open ended chamber einbracingthe focal region of the rei'iector, means for locating the lightemitting element of the lampv in the focal region and draft tubesextending in opposite directions from the chamber at a substantial angleto the axis of' the drum and to the said horizontal axis and out of thedrum, the tubes mounted to rotate also about said axis.

4. A seai'chlight comprising a drum and an arc lamp therein, means formounting said drum for rotation about a horizontal axis, a ventilatorfor said lamp comprising draft tubes mounted to rotate about said axiswith the searchlight, said tubes extending in opposite directions from apoint near the lamp to points outside the drum, said. tubes extendingsubstantially at right angles to the axis of rotation of said drum andat a substantial angle to the longitudinal axis of the drum, a gravitydamper for each tube for closing the tube when the end oi the tube fallsbelow a horizontal plane througl-i the said horizontal axis.

5. A searchlight compusing` an arc-lamp, a drum, a reflector and aventilator, the lat-v tei' having an open ended chamber embrac ing thefocalV region of the reflector, means for locating the are region of thelamp in the said focal region and for closing one end of the chamber,said ventilator having also draft tubes extending in opposite directionsfrom the chamber substantially at right angles to the axis of the drumalong a diameter of the drum and lbeyond the same.

6. A searchlight comprising an arc-lamp, a drum, a reflector whose axiscoincides with that of the drum and a Ventilating system,

the latter having an open ended chamber embracing the focal region ofthe reflector and draft tubes extending in opposite directions from thechamber at an angle to the common axis of the reflector and drum andbeyond the latter and means for turning the drum and reflector in asubstantially vertical plane passing through the common axis.

7. In a searchlight, a ventilator, an arclamp unit comprising electrodeheads and a supporting plate carrying the electrode heads of the unit,said plate electrically insulated from the heads, means for securingt-he supporting plate with its appurtenances to and in proper relationto the ventilator, and manually actuated means for securing andreleasing the supporting plate and for making and breaking the lampcircuit.

8. In combination with an arc lamp having a positive electrode said lampmounted to rotate about a horizontal axis, a double ended iue having anoutlet at each end, an intake opening for said flue at a point b'etweensaid ends, said are lamp supported to register in position with saidopening whereby the arc lamp may be placed with its positive electrodein any position of elevation above a horizontal position and preserve anupward draft in the flue against atmospheric pressure, said lue beinglocated substantially at right angles to the said axis.

9. In combination with an arc lamp having a positive electrode lampmounted to rotate about a horizontal axis, a double ended line having`an outlet at each end7 an intake opening for said tlue at a pointbetween said ends, said lamp supported to register in position with saidopening whereby the lamp may be placed with its positive electrode inany position of elevatin above a horizontal position and preserve anupward draft in the flue and a valve in i said flue for )reventing adraft flow toward the intake, said flue being located substantially atright angles to the said axis.

l0. In combination with an arc lamp having a positive electrode, adouble ended flue having an outlet ateach end, an intake opening in theflue at a point between said ends, means for rotating the lamp and flue,said lamp mounted to register in position A with said opening, wherebythe lamp may be placed with its positive electrode in any position ofelevation above a horizontal position and preserve an upward draft inthe iue, and a valve mounted in said flue for preventing the reversal ofthe draft in the flue, said valve so mounted that when the lamp isrotated, the valve is operated.

ll. In combination with an arc lamp having a positive electrode, adouble. ended `fine having an outlet at each end and an intake at apoint in between, said lamp located in juxtaposition to said intake,means for rotating the lamp whereby its positive electroce may be placedin any `position of elevation above a horizontal position, said flueserving to create a draft for the lamp by way of either end of the fluedepending upon the posit-ion of the lamp.

l2. In combination with an arc lamp having a positive electrode, adouble ended flue having an outlet at each end and an intake at a pointin between, said lamp located in juxtaposition to said intake, means forrotating-the lamp whereby its positive electrode may be placed in anyposition of elevation above a horizontal position, said flue serving' tocreate a draft for the lamp by way of either end of the flue dependingupon the position of the lamp', said lamp secured to said flue andelectric terminals on said flue and electrical connections between saidterminals and the electrodes of said lamp.

13. In combination with an are lamp having a positive electrode, adouble ended flue having an outlet at each end and an intake at a pointin between, said lamp located in juxtaposition to said intake, means forrotating the lamp whereby its positive electrode may be placed in anyposition of elevation above a horizontal position, said line serving tocreate a draft for the lamp by way of either end of the iiue dependingupon the position of the lamp.A said lamp secured to said flue andelectric terminals on said. flue and electrical connections between saidterminals and the electrodes of said lamp, a searchlight reflector and adrinn therefor, said lamp in the focal point of said reflector, saidflue secured to said drum. electrical terminals on said drum andelectrical connections between the terminals on the drum and theterminals on the ilne.

In witness whereof, we have hereunto set our hands this 7th day of July1920.

EDVIN J. MURPHY. LEONARD P. HUTT.

